Test F: The Subwoofer Is Inoperative

PINPOINT TEST F: THE SUBWOOFER IS INOPERATIVE

F1-F4:

F4-F6:

F6-F9:

F9-F12:

F12-F14:

F14-F16:

F16-F19:

F19-F21:

F22:

Normal Operation
The subwoofers are powered from a separate subwoofer amplifier for each subwoofer speaker. The enable/clip circuit 173 (DG/VT) for the 2 front subwoofer amplifiers, and circuit 174 (GY/BK) for the 4 rear subwoofer amplifiers, carries out 2 functions: to turn on the subwoofer amplifiers, and to indicate to the audio unit when the subwoofer output distortion signal reaches a damaging level. The audio unit then reduces the audio output signal to the subwoofer amplifiers. The 2 front subwoofer amplifiers receive voltage on circuit 829 (WH/VT). The 2 LH rear subwoofer amplifiers receive voltage on circuit 828 (VT/LB) and the 2 RH rear subwoofer amplifiers receive voltage on circuit 830 (PK/YE). The 2 front subwoofer amplifiers share a common ground through circuit 1204 (BK/OG). The 4 rear subwoofer amplifiers also share a common ground through circuit 1204 (BK/OG).

Possible Causes
- Fuse
- Circuit 167 (BN/OG) open or short to ground
- Circuit 168 (RD/BK) open or short to ground
- Circuit 173 (DG/VT) open or short to ground
- Circuit 174 (GY/BK) open or short to ground
- Circuit 176 (PK/LG) open or short to ground
- Circuit 179 (OR/RD) open or short to ground
- Circuit 800 (GY/LB) open or short to ground
- Circuit 801 (TN/YE) open or short to ground
- Circuit 802 (OR/RD) open or short to ground
- Circuit 803 (BN/PK) open or short to ground
- Circuit 804 (OG/LG) open or short to ground
- Circuit 805 (WH/LG) open or short to ground
- Circuit 806 (PK/LB) open or short to ground
- Circuit 807 (PK/LG) open or short to ground
- Circuit 811 (DG/OG) open or short to ground
- Circuit 813 (LB/WH) open or short to ground
- Circuit 815 (LG/OG) open or short to ground
- Circuit 816 (LG/VT) open or short to ground
- Circuit 819 (LG/WH) open or short to ground
- Circuit 820 (DB/YE) open or short to ground
- Circuit 825 (TN/LG) open or short to ground
- Circuit 827 (TN/WH) open or short to ground
- Circuit 828 (VT/LB) open
- Circuit 829 (WH/VT) open
- Circuit 830 (PK/YE) open
- Circuit 1204 (BK/OG) open
- Subwoofer amplifier
- Subwoofer
- Audio unit